Introduction: Considering the necessity of dentistry students' involvement in learning treatment topics and, in order to achieve deeper learning, this study was performed to evaluate problem based learning method and compare it to traditional method of teaching orthodontics to dentistry students.Methods: This interventional study was performed on 64, fifth year dentistry students in 2007-2008 academic years. After selection and orientation of tutors, a trainer helped them to adjust to the new method. After orientation of students about PBL method, the groups were identified and the PBL method was performed in four steps. A pretest was taken from students to assess their attitude and satisfaction about traditional method of lecture. Then, A post-test evaluated their attitude toward and satisfaction with the new method.The domains of this method were assessed by 5 point Likert scale. Results were analyzed by SPSS software using descriptive and inferential statistics.Results: The average of achieved scores out of the total score of five was as so in areas of material organization (main subjects) (3.41±0.75), internal motivation (3.41±0.7), assignments appropriateness (3.38±0.53), and suitability of evaluation method (3.67±1.17). The mean of satisfaction score was 14 out of the total score of 20 which demonstrates agreement higher than average.Conclusion: By promoting learner's internal motivation, enhancing the quality of education, and, increasing continuous learning, PBL method could prove useful in teaching dentistry students.